Viable Viral Efficiency of N95 and P100 Respirator Filters at Constant and Cyclic Flow

Gardner, Paul; Eshbaugh, Jonathan P.; Harpest, Shannon D.; Richardson, Aaron W.; Hofacre, Kent C.

doi:10.1080/15459624.2013.818228

Cited by 26 publications

(29 citation statements)

References 27 publications

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“…In this regard, rigid FFRs like P100 could maintain their form in humid and high temperature compared to the N95 [ 36 ]. This efficiency is proved by several studies, where the experimental results on the high volumetric flow showed that the mean penetration for N95 and P100 are respectively, 2 and 0.03% [ 37 ].…”

Section: Different Types Of Masksmentioning

confidence: 88%

An overview of filtration efficiency through the masks: Mechanisms of the aerosols penetration

Tcharkhtchi

Abbasnezhad

Seydani

et al. 2021

Bioactive Materials

282

322

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The masks have always been mentioned as an effective tool against environmental threats. They are considered as protective equipment to preserve the respiratory system against the non-desirable air droplets and aerosols such as the viral or pollution particles. The aerosols can be pollution existence in the air, or the infectious airborne viruses initiated from the sneezing, coughing of the infected people. The filtration efficiency of the different masks against these aerosols are not the same, as the particles have different sizes, shapes, and properties. Therefore, the challenge is to fabricate the filtration masks with higher efficiency to decrease the penetration percentage at the nastiest conditions. To achieve this concept, knowledge about the mechanisms of the penetration of the aerosols through the masks at different effective environmental conditions is necessary. In this paper, the literature about the different kinds of face masks and respiratory masks, common cases of their application, and the advantages and disadvantages of them in this regard have been reviewed. Moreover, the related mechanisms of the penetration of the aerosols through the masks are discussed. The environmental conditions affecting the penetration as well as the quality of the fabrication are studied. Finally, special attention was given to the numerical simulation related to the different existing mechanisms.

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Section: Different Types Of Masksmentioning

confidence: 88%

An overview of filtration efficiency through the masks: Mechanisms of the aerosols penetration

Tcharkhtchi

Abbasnezhad

Seydani

et al. 2021

Bioactive Materials

282

322

View full text Add to dashboard Cite

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“…For liquid particles, the penetration is however steadily increasing with respect to particle loading (Biermann et al, 1982). While many studies have investigated various initial penetration conditions (Balazy et al, 2006;Eninger et al, 2008;Rengasamy et al, 2008;Haruta et al, 2008;Grinshpun et al, 2009;Eshbaugh et al, 2009;Mostofi et al, 2010;Gardner et al, 2013;Mahdavi et al, 2014;Bahloul et al, 2014), few studies have focused on the effect of particle loading (Barrett and Rousseau, 1998;Moyer and Bergman, 2000;Mostofi et al, 2011;Rengasamy et al, 2013), particularly for N95 cases. Barrett and Rousseau (1998) tested advanced electret filter media (materials prepared for NIOSHapproved filters: N, R, and P series) with loading of NaCl [0.08 µm as the count median diameter (CMD) and 0.2 µm as the mass median diameter (MMD)] and dioctyl phthalate (DOP) (0.18 µm as the CMD and 0.3 µm as the MMD) with a 85 l min −1 constant flow and up to a 200-mg challenge aerosol load.…”

Section: Introductionmentioning

confidence: 99%

“…Nonetheless, the selection of the latter study was limited to only a single constant flow and humidity. Also, comparison of the penetrations measured for cyclic and constant flows for N95 filters have also been compared in some earlier studies (Stafford et al, 1973;Brosseau et al, 1990;Haruta et al, 2008;Eshbaugh et al, 2009;Wang et al, 2012;Gardner et al, 2013;Bahloul et al, 2014). However, the measurements were normally performed for a penetration at a specific filter loading (usually initial).…”

Section: Introductionmentioning

confidence: 99%

Particle Loading Time and Humidity Effects on the Efficiency of an N95 Filtering Facepiece Respirator Model under Constant and Inhalation Cyclic Flows

Mahdavi

Haghighat

Bahloul

et al. 2015

The Annals of Occupational Hygiene

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It is necessary to investigate the efficiencies of filtering facepiece respirators (FFRs) exposed to ultrafine particles (UFPs) for long periods of time, since the particle loading time may potentially affect the efficiency of FFRs. This article aims to investigate the filtration efficiency for a model of electrostatic N95 FFRs with constant and 'inhalation-only' cyclic flows, in terms of particle loading time effect, using different humidity conditions. Filters were exposed to generated polydisperse NaCl particles. Experiments were performed mimicking an 'inhalation-only' scenario with a cyclic flow of 85 l min(-1) as the minute volume [or 170 l min(-1) as mean inhalation flow (MIF)] and for two constant flows of 85 and 170 l min(-1), under three relative humidity (RH) levels of 10, 50, and 80%. Each test was performed for loading time periods of 6h and the particle penetration (10-205.4nm in electrical mobility diameter) was measured once every 2h. For a 10% RH, the penetration of smaller size particles (<80nm), including the most penetrating particle size (MPPS), decreased over time for both constant and cyclic flows. For 50 and 80% RH levels, the changes in penetration were typically observed in an opposite direction with less magnitude. The penetrations at MPPS increased with respect to loading time under constant flow conditions (85 and 170 l min(-1)): it did not substantially increase under cyclic flows. The comparison of the cyclic flow (85 l min(-1) as minute volume) and constant flow equal to the cyclic flow minute volume indicated that, for all conditions the penetration was significantly less for the constant flow than that of cyclic flow. The comparison between the cyclic (170 l min(-1) as MIF) and constant flow equal to cyclic flow MIF indicated that, for the initial stage of loading, the penetrations were almost equal, but they were different for the final stages of the loading time. For a 10% RH, the penetration of a wide range of sizes was observed to be higher with the cyclic flow (170 as MIF) than with the equivalent constant flow (170 l min(-1)). For 50 and 80% RH levels, the penetrations were usually greater with a constant flow (170 l min(-1)) than with a cyclic flow (170 l min(-1) as MIF). It is concluded that, for the tested electrostatic N95 filters, the change in penetration as a function of the loading time does not necessarily take place with the same rate under constant (MIF) and cyclic flow. Moreover, for all tested flow rates, the penetration is not only affected by the loading time but also by the RH level. Lower RH levels (10%) have decreasing penetration rates in terms of loading time, while higher RH levels (50 and 80%) have increasing penetration rates. Also, the loading of the filter is normally accompanied with a shift of MPPS towards larger sizes.

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“…Airborne phages have been studied mostly for filter testing (12), for phage therapy (13), and as surrogates in biodefense research (14). Phage MS2 has been the most used in these virus aerosol studies.…”

mentioning

confidence: 99%

Resistance of Aerosolized Bacterial Viruses to Relative Humidity and Temperature

Verreault

Marcoux-Voiselle

Turgeon

et al. 2015

Appl Environ Microbiol

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The use of aerosolized bacteriophages as surrogates for hazardous viruses might simplify and accelerate the discovery of links between viral components and their persistence in the airborne state under diverse environmental conditions. In this study, four structurally distinct lytic phages, MS2 (single-stranded RNA [ssRNA]), 6 (double-stranded RNA [dsRNA]), X174 (singlestranded DNA [ssDNA]), and PR772 (double-stranded DNA [dsDNA]), were nebulized into a rotating chamber and exposed to various levels of relative humidity (RH) and temperature as well as to germicidal UV radiation. The aerosolized viral particles were allowed to remain airborne for up to 14 h before being sampled for analysis by plaque assays and quantitative PCRs. Phages 6 and MS2 were the most resistant at low levels of relative humidity, while X174 was more resistant at 80% RH. Phage 6 lost its infectivity immediately after exposure to 30°C and 80% RH. The infectivity of all tested phages rapidly declined as a function of the exposure time to UVC radiation, phage MS2 being the most resistant. Taken altogether, our data indicate that these aerosolized phages behave differently under various environmental conditions and highlight the necessity of carefully selecting viral simulants in bioaerosol studies. Human populations are constantly exposed to viral particles, whether through direct or indirect contacts with an infected individual or through contaminated environments. Despite precautions, we remain at risk of exposure to infective viral particles, particularly through the airborne route. This mode of transmission is difficult to control in our everyday lives due to the ubiquitous nature of airborne particles, which may harbor infectious materials. Although the airborne route is not the most effective mode of transmission for the majority of known human pathogens, many viruses may be transmitted through this route (1). For example, measles, varicella zoster (2), and variola (3) viruses are naturally transmitted by aerosols. Other viruses, such as Newcastle disease virus, are particularly resistant to aerosolization and may potentially cause infections by the aerosol route (4, 5). On the other hand, the importance of aerosol transmission in the spread of some viruses, such as the influenza virus, is still a subject of debate (6).Aerosolized particles may be involved in viral transmission at short range through contamination of fomites by the rapid deposition of large droplets. However, true aerosol dissemination implies that sufficiently small infectious particles remain airborne for a prolonged period (2). Particles smaller than 5 m in aerodynamic diameter have the potential to travel long distances, as they sediment more slowly. However, these smaller particles harbor fewer viruses than larger particles but also less material that might protect the viruses in the airborne state. Indeed, viral resistance to aerosolization is partly dependent upon the composition of the droplet or droplet nuclei (5,7,8). Furthermore, the resistance of viruses to...

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Viable Viral Efficiency of N95 and P100 Respirator Filters at Constant and Cyclic Flow

Cited by 26 publications

References 27 publications

An overview of filtration efficiency through the masks: Mechanisms of the aerosols penetration

An overview of filtration efficiency through the masks: Mechanisms of the aerosols penetration

Particle Loading Time and Humidity Effects on the Efficiency of an N95 Filtering Facepiece Respirator Model under Constant and Inhalation Cyclic Flows

Resistance of Aerosolized Bacterial Viruses to Relative Humidity and Temperature

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